Denver, CO (SportsNetwork.com) - Josh Harrison and Gregory Polanco hit back- to-back homers in the eighth inning to lift the Pittsburgh Pirates over the Colorado Rockies, 7-5, in the finale of a three-game set.

Harrison was 4-for-6 on the day with two RBI and two runs scored, while Chris Stewart finished with three hits and crossed the plate twice for the Pirates, who avoided a series sweep with the win.

Tony Watson (7-1) earned the win despite giving up Nolan Arenado's homer in the seventh. He stayed in and pitched a scoreless eighth inning.

Brandon Barnes and Arenado both homered for the Rockies, who had their three-game win streak come to an end.

"We had some big hits," Rockies manager Walt Weiss said. "Barnes had a big one and Nolan (Arenado) had one later, but we couldn't put it away."

Rex Brothers (3-5) was tagged with the loss after surrendering both home runs in the eighth.

The Pirates scored first with two runs in the second inning. Jordy Mercer singled before Stewart and Pedro Alvarez both walked to load the bases. Harrison singled to left to plate Mercer, then Polanco hit a sacrifice fly to left to score Stewart.

Colorado got one back in its half of the second. DJ LeMahieu singled with runners on the corners, scoring Wilin Rosario.

The Rockies took the lead in the fourth. Rosario reached on a throwing error by Alvarez, then Barnes smacked one over the wall in left to put Colorado up by one. LeMahieu singled and moved over to second on a sacrifice bunt before Charlie Blackmon sent him home with a double, stretching the lead to 4-2.

The Pirates and Rockies both loaded the bases in the fifth, but neither team pushed any runs across.

Pittsburgh capitalized an inning later, however, scoring three runs in the sixth to take the lead. Stewart singled and Travis Snider hit a pinch-hit homer to right to tie the game at 4-4. Harrison singled and stole two bases after being caught in a rundown. Pinch-hitter Ike Davis doubled to right to plate Harrison and put the Pirates up 5-4.

"It was one of those weird plays ... I don't know if that'll happen again, but I'll take it," Harrison said of the rundown.

Arenado's solo homer into center tied the game at five apiece until the Pirates went ahead for the final time in the eighth.

Mark Melancon struck out two in a perfect ninth inning for his 19th save of the season.

Game Notes

Despite the win, the Pirates were a mere 3-for-16 with runners in scoring position, while the Rockies were 3-for-6 ... The Pirates outhit the Rockies, 16-10 ... The Pirates' bullpen recorded its 25th win of the season, which leads the majors ... Pirates manager Clint Hurdle picked up his 300th win in a Pittsburgh uniform.